MOLECULAR MECHANISMS ON THE REVERSIBLE MICROBODY TRANITION

可逆微生物转变的分子机制

基本信息

批准号：
09440271
负责人：
NISHIMURA Mikio
金额：
$ 7.42万
依托单位：
NATIONAL INSTITUTE FOR BASIC BIOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09440271/
关键词：
Microbody transition Arabidopsis Glyoxysomes Leaf peroxisomes Fatty acid β-oxidation Abnormal morphology マイクロボディ acyl CoA synthetase hydroxy pyruvate reductase ascorbate peroxidase トランス因子スプライシング緑葉ペルオキシゾーム突然変異株チオラーゼ形態異常 /

项目摘要

In cotyledons of some fatty seedlings such as pumpkin and Arabidopsis, microbody transition from glyoxysomes to leaf peroxysomes is observed during greening. Reverse transition from glyoxysomes to leaf peroxisomes occurs during senescence of the cotyledons. It has been suggested that the functional conversion between glyoxysomes and leaf peroxisomes is controlled at various levels, such as gene expression, protein translocation and protein degradation. A genetically approach may be an effective strategy toward understanding the regulatory mechanism(s) underlying the microbody transition at the molecular level. We screened 2,4-dichIorophenoxybutyric acid (2,4-DB)-resistant mutants that have defects in glyoxysomal function.It has been previously demonstrated that 2,4-DB is metabolized to produce a herbicide, by the action of glyoxysomal fatty acid β-oxidation in higher plants. In order to isolate mutants that have defects in glyoxysomal fatty acid β-oxidation, mutant lines of Arabidopsis … More seedlings were screened for growth in the presence of toxic levels of 2,4-DB. Twelve of the mutants survived and of these, four required sucrose for post-germinative growth. This result suggests that these mutants have defects in glyoxysomal fatty acid β-oxidation, since glyoxysomal fatty acid β-oxidation has an important role in converting sucrose from storage lipids during germination. One of the mutants lacks thiolase protein, an enzyme involved in fatty acid β-oxidation during germination and subsequent seedling growth. Another mutant has a defect in the intracellular transport of thiolase form the cytosol to glyoxysomes. Etiolated cotyledons of both mutants have glyoxysomes with abnormal morphology. In the thiolase defective mutants, glyoxysomes have tubular structures that contain many vesicles. Interaction between glyoxysomes and lipid bodies and the transport of lipids from lipid bodies to glyoxysomes during fatty acid β-oxidation are studied by using the electron microscopic analysis of the mutants. Less

在南瓜和拟南芥等一些脂肪幼苗的子叶中，在绿化过程中观察到从乙醛酸酶体到叶过氧化物酶体的反向转变，这表明在子叶衰老期间发生了乙醛酸酶体和叶过氧化物酶体之间的功能转换。过氧化物酶体在不同水平上受到控制，例如基因表达、蛋白质易位和蛋白质降解，遗传方法可能是理解的有效策略。我们在分子水平上筛选了具有乙醛酸体功能缺陷的 2,4-二氯苯氧基丁酸 (2,4-DB) 抗性突变体。 DB 在高等植物中通过乙醛酸体脂肪酸 β-氧化作用代谢产生除草剂，以分离具有乙醛酸体脂肪酸缺陷的突变体。 β-氧化、拟南芥突变体系……在 2,4-DB 有毒水平存在下筛选了更多幼苗，其中 12 个突变体存活下来，其中 4 个需要蔗糖来进行发芽后生长。这些突变体在乙醛酸酶体脂肪酸β-氧化方面存在缺陷，因为乙醛酸酶体脂肪酸β-氧化在发芽过程中从储存脂质转化蔗糖方面具有重要作用。其中一个突变体缺乏硫解酶蛋白，这是一种在发芽和随后的幼苗生长过程中参与脂肪酸β-氧化的酶，另一种突变体在细胞内将硫解酶从胞质溶胶运输到乙醛酸体方面存在缺陷，这两种突变体的黄化子叶都具有异常的乙醛酸体。在硫解酶缺陷突变体中，乙醛酸酶体具有管状结构，其中包含许多乙醛酸酶体之间的相互作用。通过使用突变体的电子显微镜分析，研究了脂肪酸β-氧化期间脂质体和脂质从脂质体到乙醛酸体的转运。